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Sept. 4, 1928.

J. H. GARTNER TIRE PRESSURE INDICATOR Filed Feb. 15, 1927 INSULATIUN 3 a %@w\% 111mg Patented Sept. 4, 1928.

uNrrs o STATES PATENT oFricE.

JOHN H. GARTNER, OF SAN FRANCISCO, CALIFORNIA, ASSIGNOR OF ONE'FIFTH T0 PATRICK S. HIGGINS, ONE-FIFTH TO TA MES I). SKELLY, AND ONE-FIFTH TO WIL- LIAM SHACKLE'ION.

TIRE-PRESSURE INDICATOR.

Application filed February 15, 1927. Serial No. 168,374.

The, present invention relates to improvements intire pressure indicators and has for its general object. to visiblyindicate to the dri'verof a motor :vehiclewhile the car is in motion whether the tires are properly inflated. It is-particularly proposed in this connection to provide'a mechanism which allows fourdifferent signals to be given by achange in the tire pressure, two signals :indicating lacleof pressure andtwo-other signals indicating over-inflation, the signals of each set-becoming activezat various 'degrees of over-,andiunder inflation.

The generalvscheme of this arrangement has been" describedin my 'co-pending application, SerialNoLl165,021 filed Jan. 31, 1927 and is hereby referred to.

It is the particular object of the present invention to disclose a particular actuating m'eansfor, azsignalling: scheme of the character. described, and 'it is-more particularly proposed to utilize magnetic means for rendering the signalling. device active. 7

-. fitFu-rther objects and-advantages of my in- ;vention will appearasthe specification pro- ,ceeds'. st p 1; 1; i i

1 The: preferred-form of my invention is illustrated. ins the, accompanying drawing in Qwhich .vta'; 51 we Figurel shows th e ,general arrangement of my; operatinggnechan sm relative to the adi tPar -of a-m t ehi lw,

Figureg2 a: sectioni taken along line 22 of Figure 1;

Figure 3 a section taken along line 33 of Figure 1;

Figure 4 a side elevation as seen from line 44 of Figure 1; and

Figure 5 a section taken along line 3-3 but looking in the direction indicated by arrows 5-5.

WVhile I have shown only the preferred form of the invention, it should be understood that various changes or modifications may be made within the scope of the claims hereto attached without departing from the spirit of the invent-ion.

Referring to the drawing in detail, it will be seen that the rim 1 of a vehicle wheel carries the tire 2, which encloses the inner tube 3 provided with the conventional valve 4, extending through the rim 1 and the felly 6. A cylinder housing 7 is mounted preferably radially relative to the Wheel and contains a piston 8, one face 9 of which is acted upon by a spring 11 held by a transvelse pin ,12. lheother:face 13.0f the piston is formed with a pocket holding a rubber cup 14, the upper edges of which bear against the inn er face of the cylinder for making an air tight seal. The upper end of the cylinder communicates through a, threaded nipple 16, a flexible tube 17 and a universal valve 18. with the conventional valve 4 so that the chamber formed in the upper end of the cyl- 1nder is always subjected to the pressure prevailing within the tire. The universal valve 18 is of standard construction, its object being to open the passageway in the conventional valve 4, and to provide a side valve 19 through which the tire may be inflated.

The piston 8 has a rack rod 21- extending mg 26, secured to the. cylinder by bolts 27..v

F ixedto a stationary part of the motor vehicle isa; casing 28 having an armature 29 pivoted therein, as shown at 31. The armaturevis pivoted centrally and provides two arms 32 and 33 vand is normally held in a. plane paralleltothe plane of the wheel,

the'pivot 31 being equidistant from the axis of rotation with the pivot 24,'and being arranged so that the armature occupies a radial position. The armature has a spring niember 34 secured thereto, which presents four different spring contacts 36, 37, 38, and 39, the' former two extending outwardly from the pivot 31 and the latter two extending inwardly, and the four contacts being adapted for engagement with four stationary contacts 41, 42, 43, and 44 connecting through four wires 46 with circuits, not shown in the present drawing but described and illustrated in the co-pending application. Screws 47 hold the wires 46 in place. A spring 30 holds the armature in normal position.

The operation of my device is as follows: When the pressure in the tire is normal the piston 8 retains the position indicated in Figure 1, so that the magnet occupies an exact midway position, and when passing the armature 29 draws on both arms thereof with equal force so as to leave the armature unefi'ectetl. ll'hen the pressure in the tire changes and decreases the spring 11 forces the piston upwaxdywhereby the magnet- 23 is swung downwardly and now becomes active upon the inner-arm 32 of the armature when passing the same. The inner arm 32 being attracted. the outer contact 31' engages with the stationary contact 41 and closesa ei rcuit, indicating to the driver through some suitable signal, as for instance, the lIght-ing of a lamp that the pressure in the tire runs low- As the pressure still further decreases the second contact 36 engages the contact- 42, thereby closing a second circuit and lighting a second lamp,- indicating to the driver that the tire is further reduced in pressure, the arrangement being preferably adjusted in such a manner that the first si nal becomes- -aetive before the pressure is retlirccd to such an extent that it would be dangerousto continue t'll'fllllg, while thesecond signal becomes active when the tire is flat.

On an increase in pressure-the magnet- 23 becomes active on the upper -a rm33 of the armature and successively engages contacts 3S antl44 and the c0ntacts'39 and 43 for simifire so as to be-periodical y-passed by then-iagnet-ic element a'igd'to he subject-t0 the influence thereof,;the operating-member and the magnetic elementvbeingarrariged relative to-on'e another so that-'tho-jatter is'responsive tothe'former only-when the magnetic elementfisrnoveti ziniabnormal osition due to an abnormal, in the tire pressure,

2. In a pressure indicatbr for a pneumatic tire, a movable magnetic element. revolving with the tire, means for moving the same in l'lSlXHlSC to changes in the tire pressure, and an electriccircuit having a switch element mounted in operative proximity of the tire so as to be pcriodicallypas-cd by the magnetic element. and to be subject to the is:- lluencc thereof, the switch element and the magnetic eienzcutbeing arranged relative to one another so-tha-tthe bitter is responsive to the former only when the. magnetic elementis moved to an abnormal position due to an abnormal change'in the tire pressure.

3. In a pressure indicator for a pneumatic tire. a movable magietic element revolving with the tire, means for moving the same in response to changes in the tire pressure and an electric. circuit having a switch element mounted in operative proximity of the tire so as to be periodically passed by the magnetic element and to be subject to the influence thereof, the switch elementbeing a pivoted lever and the magnetic element being mounted so as to normally pass the fulcrum thereof and to leave the lever unaffected but to move in the direction of'one-oi the arms of the lever under the influence of a change in the tire pressure for operating the said arm.

'4. In a' pressure indicator for a pneumatic tire, a movable magnetic element revolving with the tire, means for moving the same in response'to changes -in. the tire pressure, and an electric circuit havinga 'suzitch element mounted in operative-proximity of theitire so as to be periodically-passedby the mag-' netic element and to be subject to the in 'fiuenc'e thereofi'the switch eternent beinga 'pivotedlever-and the magnetic -element being mounted relative thereto so as to normally leave the'switchelement unaffected-but tooperate the same when its position is changed due to a change in the tire pressure.

J GilRTNER 

